International Journal of Sediment Research最新文献

{"title":"Modeling the hydraulic roughness of a movable flatbed in a sand channel while considering the effects of water temperature","authors":"Junzheng Liu ,&nbsp;Jinliang Zhang ,&nbsp;Zhe Huang ,&nbsp;Haijue Xu ,&nbsp;Yuchuan Bai ,&nbsp;Gang Wang","doi":"10.1016/j.ijsrc.2024.11.004","DOIUrl":"10.1016/j.ijsrc.2024.11.004","url":null,"abstract":"<div><div>The prediction of the flow resistance (usually quantified as the hydraulic roughness) of a movable flatbed is a key issue affecting the calculation accuracy of flood levels in river training projects. Bedload motion on a movable flatbed causes additional energy loss and increases hydraulic roughness. Several theoretical and empirical predictors for characterizing this phenomenon have been proposed, but the accuracy and physical basis of these models should be improved. In this study, the total energy dissipation rate is separated into two components: the energy dissipation rate due to grain drag and the additional energy dissipation rate due to bedload motion. Following the energy dissipation rate balance equation, a new predictor was proposed for movable flatbed flows. The water temperature was empirically coupled with the fluid viscosity and its associated physical variables. A new empirical relation between two dimensionless flow‒sediment combination variables was established to demarcate the various bedform transitions induced by the water temperature. The new predictor was compared with other predictors, and the prediction results were compared to the measured data. The error metric showed that the new predictor provided the highest accuracy, with ∼88.5% of the 826 data points falling within the ±30% error band. The new predictor suggested that the additional drag is nonlinearly proportional to the grain drag, and the scale factor between these two parameters is related to five flow‒sediment variables. In addition, the ability of the new predictor to quantify water temperature effects was examined. The predicted resistance exhibited three change modes with increasing water temperature, and the results suitably agreed with the measurements. The effect of the water temperature on the resistance of a movable flatbed is jointly controlled by the suspension number and roughness Reynolds number. This study provides an effective predictor that can be used by decision makers for modeling the hydraulic roughness of a movable flatbed.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 31-44"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological properties of two-dimensional and three-dimensional bedforms in open channel flow: A flume experiments study","authors":"Wenhong Cao ,&nbsp;Xu Geng ,&nbsp;Chunjing Liu ,&nbsp;Lingfeng Zhang","doi":"10.1016/j.ijsrc.2024.09.007","DOIUrl":"10.1016/j.ijsrc.2024.09.007","url":null,"abstract":"<div><div>Bedforms are formed by sediment particles under the action of flow, which in turn affect flow and sediment movement. However, the fundamental mechanisms behind the formation and development of bedforms under varying flow conditions, the interconnection between sediment particle movement and bed morphology development, as well as the influence of bedforms on flow and sediment transport, are still not well understood. In the current study, the moveable bed load transport flume experiments under different flow conditions were done, and the development processes of two-dimensional and three-dimensional dunes formed under different flow intensities were simulated. The detailed structure of the bedforms was measured by laser scanning technology, the characteristics of the bedforms were analyzed in detail, and the relations between the formation of the bedforms and the movement of sediment particles are discussed. The results found that the correlation coefficients of the longitudinal profile curve can serve as a quick reference for distinguishing two-dimensional and three-dimensional dunes. When the crestline ratio is used as the criterion for two-dimensional and three-dimensional dunes, the relative amplitude of the dune crestline and the included angle with the flow direction should also be comprehensively considered. The lee side angles of dunes calculated using the triangle generalization method and local section tangent method are compared and show that the values obtained by the former method are only about half of that of the latter. It is also found that the lee side angles of dunes are related to the dune height. The superimposed dunes generally exist in the downstream area of the stoss side of the dunes. The local bed slopes on the stoss side of the dunes show reverse slopes. The superimposed dunes improve the local bed height and further increase the reverse slope degree of the stoss side. A streamwise ridge is an important form located in the upstream area of the dunes stoss side, and they are symmetrically distributed on both sides. Multiple streamwise ridges divide the stoss side of the dunes into relatively independent movement areas, restricting the movement of sediment particles to specific regions. According to the distribution characteristics of bed morphologies, the effects of dunes on sediment particle movement and flow energy consumption are analyzed.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 15-30"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influences of sedimentation on overflow properties of sharp-crested weir","authors":"Mohammad Mehdi Farzanmehr,&nbsp;Jahanshir Mohammadzadeh-Habili","doi":"10.1016/j.ijsrc.2024.10.008","DOIUrl":"10.1016/j.ijsrc.2024.10.008","url":null,"abstract":"<div><div>A sharp-crested weir is the simplest type of weir and is mainly used for discharge measurement in open channels. The surface profile of an ogee weir also is designed based on the lower nappe profile of the free jet passing over a sharp-crested weir. In the current study, influences of sedimentation on the discharge coefficient and lower nappe profile of a sharp-crested weir were experimentally investigated. The results indicated that for a specific discharge value, an increase in upstream sedimentation depth results in the reduction in the water level of the approach flow to the sharp-crested weir, and, consequently, a reduction in the weir water head. As the discharge coefficient is inversely influenced by the weir water head, increases in the sedimentation depth resulted in raising the discharge coefficient of the sharp-crested weir up to 42%. Furthermore, the results indicated that with increases in upstream sedimentation depth, the lower nappe profile of the free jet passing over the sharp-crested weir tends toward that of a vertical drop. Under upstream sedimentation, the discharge coefficient of the sharp-crested weir is mainly influenced by the weir's effective height (difference between weir height and sedimentation depth) and it is minimally influenced by sediment grain sizes. Using the experimental results supported by dimensional analysis, the discharge coefficient of the sharp-crested weir was accurately derived as an increasing function of the ratio of weir water head to weir effective height.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 172-181"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Source distribution, ecological risks, and controlling factors of heavy metals in river sediments: Receptor model-based study in a transboundary river basin","authors":"Abu Reza Md Towfiqul Islam ,&nbsp;Abu Hena Md Fazla Rabbi ,&nbsp;Amit Hasan Anik ,&nbsp;Rahat Khan ,&nbsp;Md Abdullah Al Masud ,&nbsp;Grara Nedjoud ,&nbsp;Abubakr M. Idris ,&nbsp;Md Naimur Rahman ,&nbsp;Venkatramanan Senapathi","doi":"10.1016/j.ijsrc.2024.10.001","DOIUrl":"10.1016/j.ijsrc.2024.10.001","url":null,"abstract":"<div><div>In the context of transboundary rivers, which constitute intricate fluvial ecosystems, the persistent threat of heavy metals (HMs) contamination poses significant risks to ecosystem health. In this study, ecotoxicological hazards, governing factors, and the distribution of nine HMs (uranium (U), lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu)), as well as sediment characteristics (sand, silt, clay, organic matter, and pH) are assessed within the sediment. The current investigation encompasses the analysis of twenty-seven sediment samples, utilizing inductively coupled plasma mass spectrometry, in the transboundary river basin of Bangladesh, specifically the Teesta River. Notably, the findings underscore the predominance of Cd as a contaminant, responsible for 51.85%, 81.84%, and 100% of the geo-accumulation index, contamination factor, and enrichment factor, respectively. The Teesta River emerges as moderately to highly polluted, with cumulative probabilities of 7.4%, 85.2%, and 7.4% denoting “medium”, “high”, and “priority” pollution levels, respectively. Regions in the upstream and downstream middle sections of the study area exhibit relatively higher pollution levels, particularly in proximity to Kaunia Upazila in the Rangpur district. Ecologically, the potential risk index indicates a low likelihood of ecological impacts at 77.8%, alongside a moderate risk observation of 22.2%. The current results attribute the distribution of these HMs to the pH and organic matter content within the sediment, serving as pivotal factors. To unravel the origins of the HMs, the positive matrix factorization (PMF) model successfully identifies four contributing factors, primarily from geogenic sources. Validation of the PMF model through Spearmen correlation and principal component analysis (PCA) reveals a consistent pattern, affirming its efficacy in this analysis. Within the region, HM sources are identified as originating from anthropogenic activities such as irrigation, industrial discharges, and domestic effluent, in addition to substantial inputs from geogenic sources. Recognizing the transboundary nature of metal pollution, the current study underscores the imperative for continuous and vigilant monitoring, coupled with the implementation of robust management practices. The interplay of both anthropogenic and geogenic factors necessitates a comprehensive approach to effectively and sustainably combat HM contamination.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 45-61"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flash floods on the northern coast of the Black Sea: Formation and characteristics","authors":"Ludmila Kuksina ,&nbsp;Pelagiya Belyakova ,&nbsp;Valentin Golosov ,&nbsp;Ekaterina Zhdanova ,&nbsp;Maxim Ivanov ,&nbsp;Anatoly Tsyplenkov ,&nbsp;Artem Gurinov","doi":"10.1016/j.ijsrc.2024.10.003","DOIUrl":"10.1016/j.ijsrc.2024.10.003","url":null,"abstract":"<div><div>Flash floods are one of the most dangerous hydrometeorological events in the world. The current study investigates flash floods on the northern Black Sea Coast. The data about stochastic and relatively stable factors of flash flood formation (such as hydrological, meteorological, lithological, geomorphological, and anthropogenic parameters) were collected for 22 events. The main trigger of flash floods is heavy rainfall of high intensity in the region but in some cases flash flood occurrence is connected with combinations of several “non-critical” factors. The small watershed area (≤351 km²) of river basins experiencing flash floods promotes very rapid flow concentration. Analysis of extreme precipitation demonstrates significant increasing trends in river basins on the Crimean Peninsula and decreasing a maximum precipitation amount in 5 days (r5d) and 1 day (r1d) in river basins in the Caucasus Black Sea Coast in the 21st century as determined by processing of Integrated Multi-satellite Retrievals for Global precipitation measurement (IMEGR) satellite data. At the same time land network data indicates increasing r5d at the Anapa and r1d at the Tuapse meteorological stations in 1961–2020. More frequent occurrence of flash floods has been suggested in the area due to statistical analysis of the longest precipitation ranges. The main reason for significant social and economic damage is uncontrolled human activity in flooded areas on the northern Black Sea Coast.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 192-207"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of sand and mud transport processes in currents and waves by time-dependent 2DV model","authors":"Leo van Rijn ,&nbsp;Karel Meijer ,&nbsp;Kris Dumont ,&nbsp;Jan Fordeyn","doi":"10.1016/j.ijsrc.2024.10.009","DOIUrl":"10.1016/j.ijsrc.2024.10.009","url":null,"abstract":"<div><div>This paper presents a time-dependent, two-dimensional vertical model for the simulation of sand and mud concentrations, transport and bed level changes in tidal conditions with or without surface waves. The model solves the advection-diffusion equation for suspended sediment. The horizontal velocities and the sediment mixing coefficients are modelled as function of x, z, and t. The settling velocity is constant or modelled as function of the sediment concentration. The sediment mixing coefficient over the water depth is described by flexible expressions based on current and wave parameters which can be modified easily in the input file. To represent mud flocculation and hindered settling processes, the settling velocity can be set as constant or concentration-dependent (input). The bed boundary condition is modelled as a bed concentration as function of the bed-shear stress. The model is valid for low and high sand and mud concentrations including fluid mud concentrations. The numerical SUSTIM2V-model is herein used to simulate sand and mud transport as measured in tidal waters. The model is also successfully used for simulation of high mud concentrations in the near-bed region as measured in the mouth of the Amazon River. The model has also been used to simulate scour along an offshore caisson-type foundation structure.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 1-14"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the performance of transport equations through long-term records of integrative measured bedload data","authors":"Andrea Lammer ,&nbsp;Rolf Rindler ,&nbsp;Michael Tritthart ,&nbsp;Marcel Liedermann ,&nbsp;Markus Moser ,&nbsp;Dorian Shire-Peterlechner ,&nbsp;Sabrina Schwarz ,&nbsp;Helmut Habersack","doi":"10.1016/j.ijsrc.2024.11.001","DOIUrl":"10.1016/j.ijsrc.2024.11.001","url":null,"abstract":"<div><div>Temporal and spatial variability and a wide range of measured transport rates at comparable flow rates are well-known characteristics of the bedload transport process but represent substantial difficulties in practice and for load calculation. The possibility of measuring the bedload transport process has increased in recent years through the use of technically advanced methods. Since 2011, an integrative bedload monitoring system has been operating on the Urslau River in Austria and has been continuously observing the transport process. This long-term integrative dataset provides the basis for comparing calculation results from commonly used bedload transport formulae with measured data. On the basis of 27 high sediment transport efficiency events, as well as 75 events with reduced sediment availability and 34 events with low sediment availability, this study compares the measured and calculated bedload volumes. In addition, a wide range of measured bedload transport rates are presented for comparable discharges, and values in this range are represented by the formulae shown. The performance of the transport equations is improved by considering measured data from integrative bedload monitoring and by classifying bedload events. The results presented here indicate that, depending on the question considered and by selecting the appropriate formula, it is possible to achieve improved calculation results for practice that are comparable to the measured values.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 158-171"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the settling of irregularly shaped sediment particles from the source region of the Yangtze River","authors":"Xiaoyong Cheng ,&nbsp;Zhijing Li ,&nbsp;Yujiao Liu ,&nbsp;Zhongwu Jin ,&nbsp;Yinjun Zhou ,&nbsp;Yisen Wang ,&nbsp;Guiqiao Wang ,&nbsp;Junfeng Han ,&nbsp;Zhixian Cao","doi":"10.1016/j.ijsrc.2024.11.005","DOIUrl":"10.1016/j.ijsrc.2024.11.005","url":null,"abstract":"<div><div>Settling plays a pivotal role in sediment transport and morphological evolution of alluvial rivers. Sediment particles in the source regions of large rivers are more likely to feature irregular shapes due to less abrasion than in lower reaches of the rivers. However, the settling of irregularly shaped sediment particles from the source region of a river has to date remained poorly understood. Here, sediment particles were sampled from the Tuotuo River basin in the source region of the Yangtze River. A total of 28 experimental runs were done in a purpose-built settling cylinder to investigate the settling of the sediment particles, with particle Reynolds number, <span><math><mrow><msub><mtext>Re</mtext><mi>p</mi></msub></mrow></math></span>, defined using terminal settling velocity, ranging from 0.22 to 5,939. The results demonstrate that large <span><math><mrow><msub><mtext>Re</mtext><mi>p</mi></msub></mrow></math></span> and irregular particle shape favor unstable settling behavior with wobbling motion and intense velocity fluctuations. An irregular particle experiences larger drag, and, thus, attains a lower terminal velocity than an equivalent sphere, and the shape effect which reduces terminal velocity tends to become significant with increasing <span><math><mrow><msub><mtext>Re</mtext><mi>p</mi></msub></mrow></math></span> and decreasing Corey shape factor. The measured terminal velocities are compared with five empirical formulas. It is shown that the formulas of Dietrich, Haider and Levenspiel, and Wu and Wang are favorable to use (within the range ±20% of the measured data), whereas Zhang's formula and van Rijn's formula may considerably overestimate the terminal velocity, as no shape descriptor is incorporated to account for irregular shape effects. The current study facilitates a new experimental dataset that may be utilized to further investigate sediment settling dynamics. Also, it has direct implications for enhancing the understanding of morpho-dynamics in the source region of the Yangtze River, which may experience significant changes in response to climate change and anthropogenic activities.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 62-77"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical composition of sediment and macrozoobenthos of small urban lakes, the Republic of Karelia, Russia","authors":"Evgeny Savosin ,&nbsp;Zakhar Slukovskii","doi":"10.1016/j.ijsrc.2024.10.005","DOIUrl":"10.1016/j.ijsrc.2024.10.005","url":null,"abstract":"<div><div>Assessing the benthic communities in water bodies under increasing anthropogenic pressure seems to be an urgent task of scientific research aimed at short-term and long-term monitoring of water bodies. This study focuses on the chemical composition of modern sediment and the current state of macrozoobenthos of small lakes in the Republic of Karelia (Kitaiskoe and Plotichie) influenced by anthropogenic factors. It was discovered that the lakes of Medvezhyegorsk have a higher concentration of heavy metals (such as lead (Pb), cadmium (Cd), molybdenum (Mo), and antimony (Sb)) compared to the Earth’s crust and natural background levels. The current study established the significant impact of industry and transportation on the movement and build up of pollutants in these lakes. The qualitative and quantitative parameters analyzed for the benthic communities in the littoral and profundal zones included the species diversity, the structure of dominant species, and their percentage in the samples. According to the level of macrozoobenthos development, both reservoirs (lakes) were classified as mesotrophic, and according to the values of the chironomid index “K” as moderately polluted. The Pantle–Buck method (saprobic index) showed that the lakes can be classified as polluted (water quality class 4). Macrozoobenthos groups most tolerant to environmental conditions, for example, Chironomidae larvae, prevailed in the studied urban lakes. The economic development of the lakes leads to ecosystem transformation and long-term eutrophication over time affecting the biotic indicators of surface water quality. The results obtained can serve as a basis for complex environmental monitoring of the urbanized territories in the taiga zone.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 119-128"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of grade control structures on riverbed degradation","authors":"Weiming Wu ,&nbsp;Ruihua Nie ,&nbsp;Kai Wei ,&nbsp;Bruce W. Melville ,&nbsp;Asaad Y. Shamseldin ,&nbsp;Lu Wang","doi":"10.1016/j.ijsrc.2024.10.004","DOIUrl":"10.1016/j.ijsrc.2024.10.004","url":null,"abstract":"<div><div>Sediment flux of many rivers has been significantly reduced due to human activities caused by economic development, leading to increasingly severe riverbed degradation. To prevent riverbed degradation, grade control structures (GCSs) have been widely applied in degrading channels. Existing studies have not provided a good understanding of the effects of GCSs on flow characteristics and bed morphology in degrading channels, limiting the management of degrading channels. A series of flume tests with no sediment supply are conducted to investigate the effects of GCSs on upstream water levels and riverbed morphology in degrading channels. The experimental results indicate that: (1) in the initial stage of degradation, the water surface slope in the backwater reach is linearly and negatively correlated with the GCS-height Froude number, based on the average flow velocity upstream of the backwater reach due to GCS and the height of GCS; (2) the effective protection bed length upstream of GCS is approximately equal to the length of the reach where the flow velocity is less than the critical velocity for sediment motion in the backwater zone; (3) for sequential GCSs, the effective protection bed length will decrease if GCS is located in the backwater reach of the downstream GCS. A semi-analytical calculation method of the effective protection length and equilibrium bed profile upstream of GCS in degrading channels is proposed based on the critical condition of sediment motion and weir flow formulas. The computed values by the proposed calculation method agree well with the experimental data of the present study.</div></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"40 1","pages":"Pages 108-118"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}